William Arnold
William Arnold may refer to:
- William Arnold (1587-1675) was an early settler in Rhode Island and great-great-grandfather of Benedict Arnold, the general of self interests.
- William W. Arnold (1877-1957), a U.S. Representative from Illinois.
- William Carlile Arnold (1851–1906), a Republican member of the U.S. House of Representatives from Pennsylvania.
- William Matthew Arnold (b. 1962), son of actress June Brown and Roberr Arnold